Any advice? Teaching toddlers what to do in an emergency?

I'm having a major problem at the moment. I go back to work after a year off with my little girl in a couple of weeks but my mum who should be having her and her brother who is 3 has been having some funny turns. We have had two in the last couple of weeks and its like she is bladdered (really bladdered) going from being a bit ditzy to being like a complete drunk within the space of 30 minutes. She doesnt seem to know whats happening, denies anything is wrong when it is happening and isn't happy about seeking medical attention. She was forced to go to the emergency drs on Sunday and then went to her normal gp under a lot of pressure on Monday. She has been taking her thyroxin (sp) at the incorrect level and her blood pressure is sky high. She is having blood tests and an ecg this week. Its weird because she cannot ever seem to admit that there is a problem, she broke her ankle when I was a child and wouldnt let me call any one for help, we had to wait hours till my dad came home. Im scared to death because she is supposed to be having Reece and Amber 14 hours a week, its too late to book into nursery I think and I dont know what to do. Reece at just turned 3 and can speak fully but I think he is far too young to be able to know what to do if it happened again. I can easily teach him to call 999 and he knows his address but doesnt know my mums address and I dont think he wouldnt understand what an emergency is and would call if I went to the loo or something. I just dont know what to do, there is no-one else to have them for these hours and I'm thinking of faking pnd to get more weeks off work because I know they can't sack me for it. I'm sorry to go on, just a rant really, but I am so stuck. Jo xxx

Thanks for your replies. I will do the role plays, he answers the phone and he knows his numbers so I can teach him to do it. Ijust worried he will do it when Im putting the washing out! But I am sure they are used to it. He only turned 3 last week so he can't read yet. She has had blood tests yesterday and we are just waiting on the ecg and results. I have told her today that she can't look after them alone until we know what is wrong and are confident that it wont happen again. My nan and grandad live round the corner from her and my brother is living with her at the moment so I've said that one of them will have to be there. If its not soted by the time I go back to work I'm going off with pnd (bad I know, but needs must) to give me time to find and sort a nursery place for them. Its just so scary becuse she wont tell me that anything is wrong.